Method of making tubes



Oct. 25, 1927.

L. T. FREDERICK METHOD OF MAKING TUBES Filed Aug. 13, 1923 Patented Oct. 25, 1927.

PATENT OFFICE.

LOUIS T. FREDERICK, F VALPARAISO, INDIANA, ASSIGNOR TO FIBROC INSULATION COMPANY, OF VALPARAISO, INDIANA, A CORPORATION OF INDIANA.

METHOD OF MAKING TUBES.

Application filed August 1a, 1923. Serial no. 657,182.

My invention relates to the production of tubes of that class in which a sheet of fibrous material is wound upon a mandrel and the various turns secured together by means of an adhesive. The ractice has existed for many years of pro ucing tubes by winding a sheet of paper or other fibrous material around a mandrel until the desired thickness is built up, the various layers being held together by means of an adhesive. Various materials have been employed including paper and cloth but in all previous methods so far as I am aware the material has reached the mandrel in a saturated and 1 stretched condition. This has several disadvantages. In the first place it callsfora considerable quantity of adhesive, involving a corresponding expense. Second, the amount of moisture in the adhesive has caused the fabric to stretch with the result that the sheet goes on to the mandrel in moist and also in stretched condition and must remain on the mandrel until it is dry. If quick drying means are provided they add a complication to the process. If they are omitted a large number of mandrels must be employed if the tubes are to be roduoed in quantity, for obviously the man 1 must remain in place imtil the tube is Furthermore the drying involves shrinking and, it becomes necessary to use a stripping machine to remove the tube from the mandrel. The object of my invention is to provide a process in which a smaller amount of adhesive will be'required, heating will be dispensed with, shrinkage will be avoided, and the time and number of mandrels required be reduced to a minimum.

Generally speaking, I accomplish my purpose by employin as the sheet material a paper which is ca endered or glazed to such an extent that it will prevent for a considerable period penetration of the adhesive into the body of the material. In other words, the paper is substantially non-absorbent; also I apply to the surface of the sheet only so much adhesive as will be necessaryto form a thin surface coating for it. The sheet is then wound upon the mandrel under pressure bail: without heat.

In e accompanying drawings I have illustrated one type of machine by'which my method may be carried out, although it will be understood that the machine is illustra tive only and may assume various forms in practice.

In the drawings Figure 1 is an end elevation of the machine, and

Figure 2 is a front elevation thereof, parts being broken away to better reveal the construction,

0 Like numerals denote like parts in the two views.

In the machine illustrated there is a main frame 1. A storage roll 2 is rotatably mounted on the frame and provided with a friction device for preventing the roller from unwinding too fast. This consists of a sheave 4 with a weighted belt 5 passing around it. From the storage roller the sheet material. 8, from which the tube is to be made, passes between lwvo rollers 10 and 11. The lower roller 10 dips into a tank 12 containing the adhesive. As an example the adhesive may be a solution of dextrine or it may be a heavy viscosity varnish, or shellac, or insulating glue.

The roller 10 is journaled in boxes 14' which slide vertically and these boxes are continuously pressed upward by compression springs 16. The upper roller 11 limits the upward movement of the lower roller and between them they remove surplus adhesive so that a thin coating of the adhesive willbe applied to one side of the sheet. The pressure is regulated in such manner as to permit but a small amount of adhesive to remain upon the sheet. 7

From the rollers 10, 11 the sheet passes over a roller 18 which is journaled 1n the main frame and cooperates with the mandrel 20. Said mandrel is mounted upon a .shaft 22 which is rotatable and vertically movable within vertically slotted posts 23. A roller 24, which is also journaled in the main frame, is in position to contact the mandrel 20. The mandrel is under constant pressure toward the rollers 18 and 24 due to' the action of a pressure roller 26 journaled in arms 28 pivoted upon stationary pins 30. The weight of the roller may be augmented by a tension spring 32, whic is fastened i arm 28 and to the post 34, in which shaft 30 is journaled. The spring is so arranged that when the arm is in horizontal posit on it will pull downward upon it to increase the pr, and when the arm 12 swung to upright position will move past the center of shaft 30 and tend to hold arm 28 in upright position as shown in dotted lines in Figure 1.

' The operation will be readily understood. When the parts are brought to the position shown in Figure 1 if the mandrel is rotated it will wind the strip 8 6f fibrous material around it, drawin it between the two rollers 10 and 11 by which a small amount of adhesive will be applied. The proper degree of pressure of the layers or turns of the strip is produced by the roller 26, which operates under the action of the springs 32 in addition to the weight of the roller itself.

The apparatus which I have just described is not greatly different from apparatus previously known for the production of tubes of this character. The important features of my process reside in the employment of a fabric adapted to resist rapid penetration of liquid adhesive and the employment of means for applying to the fabric in cold condition a small amount of the adhesive. An additional characteristic of the invention, which follows as a natural sequence, is the dispensing of heating means for driving ofi the moisture, and the employment of a noncontracting mandrel (contracting mandrels having been found necessary in many cases in order to make it possible to remove the finished tube from the mandrel). Such a contracting mandrel is shown, for example, in'Ball Patent 148,544.

As a result of my method the adhesive forms merely a surface coating on one side of the sheet and is present in such small,

quantities that there is no saturating or stretching of the paper and the tube will be ready for removal from the mandrel just as of the adhesive into the body 0 -mandre1 immediately, thus releasing the latter for immediate re-use. Furthermore the operation can be greatly speeded up and the output correspondingly increased, for it is not necessary to slow up the machine to wait for the driving off of any excess moisture.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. The method of making tubes which includes applying a thin coating of adhesive to a sheet of paper which is calendered or glazed to such an extent that it will prevent for a considerable period enetration f the paper and winding the sheet upon a mandrel whereby to avoid stretching the paper during the formation of the tube.

2. The method of making tubes which includes applying a thin coating of adhesive in a cold'condition to'a sheet of paper that is calendered or glazed to such an extent that it will prevent for a considerable period penetration of the adhesive intothe body of the paper and winding the sheet upon a mandrel under pressure.

I In witness whereof, I have hereunto subscribed my name.

LOUIS T/FREDERIGK. 

